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DID YOU KNOW high speed taxi testing can potentially void your insurance policy?

LRingeisen

Well Known Member
Many times Vans owners call to increase their coverage from ?Builders? (not in motion coverage) to ?Ground and Taxi.? The Ground and Taxi only covers the hull of your aircraft until you reach the active runway thereby excluding hull coverage for high speed taxi test. The main reason for this is that even though you may not intend to get airborne it can happen fairly easily and unexpectedly. If you are unprepared it can be very a dangerous situation; you may not have much gas in the tank, you may not be entirely ready to solo your freshly built aircraft, and whole host of other reasons. Typically people do not opt for this coverage because by the time they are ready for this coverage they are only a few short weeks away from flying. It?s of little financial value to switch to Ground and Taxi unless it?s going to be longer than a month before you?re ready to fly.
 
Interesting. Personally I'd recommend just not doing high speed taxi tests altogether -- I see no upside and just a lot of risk in that particular test.
 
I guess it depends on what 'high speed' means. I did one taxi at about 30 knots to condition the brake pads.
 
I did a few, but, I had full insurance coverage, ARROW, transition training, weather check, full pre flight and run up, fully strapped in and aircraft ready for flight. wanted to confirm fuel system and dynamic full power RPM, ground handling and brake pad seat, discovered CS prop needed adjusting, Paid very close attention to speed. I can see where a lot of things can go wrong, like if you were not ready to get air born, but on the other hand, good practice for when that deer or what ever causes you to abort a take off....
 
I did enough to confirm the prop governor was set correctly and condition the brake pads, you pretty much have to do that.
 
A good friend who was an early builder of a GlassAir 1 did the high speed taxi test thing. Now cowl, limited fuel, limited experience in high performance planes, etc.

Before he got the throttle in the plane was 50 fee off the ground and with a short runway under him, he couldn't chop the throttle and land.

So his "unofficial" first flight occurred before he had his airworthiness certificate, weight and balance, or cowling.

Lucky for him there wasn't an issue with the plane and it flew just fine without the cowl on it.

I agree, high speed taxi tests are not a good thing.
 
"High speed" is perhaps a relative term and needs clarification in this context. I don't think I ever exceeded 30 knots during my testing and brake pad wear-in, though I did several runs up to that speed. Anything over that speed, yes I would agree, is just not necessary and presents unwarranted risk. You want to know that your engine responds to rapid throttle advancement, that the governor on a CS prop catches it before overspeed, that you don't have a severe tire issue at higher speeds, and that your brakes are effective and somewhat broken in before first flight.
 
It may be different for different kinds of brakes, but the instructions that came with mine (stock brakes from Van's) said to taxi at 1700 RPM while holding enough brake pressure for 5-10 mph for 1500 feet, let them cool, then test holding power.

That doesn't sound like a high-speed taxi test to me.

I'm just not sure what one expects to learn at "high speed taxi" that you can't learn at a normal taxi, during a full-power static run-up, etc., that doesn't involve the risk of accidentally flying when not prepared for it. Engine response can be tested without it. Prop governor, too. Etc...

To each his own, i guess, but given the number of stories about people who inadvertantly become airborne while doing this, I never saw the need for it.
 
It may be different for different kinds of brakes, but the instructions that came with mine (stock brakes from Van's) said to taxi at 1700 RPM while holding enough brake pressure for 5-10 mph for 1500 feet, let them cool, then test holding power.

That doesn't sound like a high-speed taxi test to me.

I'm just not sure what one expects to learn at "high speed taxi" that you can't learn at a normal taxi, during a full-power static run-up, etc., that doesn't involve the risk of accidentally flying when not prepared for it. Engine response can be tested without it. Prop governor, too. Etc...

To each his own, i guess, but given the number of stories about people who inadvertantly become airborne while doing this, I never saw the need for it.

My IO 360 A1A CS with EFII static RPM was 2500 RPM. @ 30 kts HST test it was at 2950 RPM :eek: made a prop adjustment, and all good now.
 
... did the high speed taxi test thing ...
... with a short runway ...

I agree, high speed taxi tests are not a good thing.

Sounds like poor pilot decision making in general was a larger problem than the high speed taxi tests in particular.
 
Sounds like poor pilot decision making in general was a larger problem than the high speed taxi tests in particular.

Certainly, however, bad decisions can often be attributed to lack of education or awareness. Most people don't knowingly make bad decisions, although the human condition is full of self justification of them.
Although I am of the "there is little if any benefit crowd", others may choose differently. I appreciate the OP pointing things out from an Insurance point of view.
 
I uncovered and was able to rectify some severe gear leg shimmy and vibration in my HS taxi tests which I terminated at 35-40 kts. Never any danger of flying and there was 5000 feet of runway so no pressure to brake hard even.

All new aircraft OEMs do HS taxi tests, just have to be done in a professional and planned way like any part of the test program should be.

Just my opinion, but people who get into trouble or actually take off during HS taxi tests have neither a good plan in place nor should they probably even be in the pilots seat. Is it really that hard to pull back the throttle at 35 knots and start the test from a runway with a safe length to begin with? I'd very concerned about people's skills, qualifications and judgement process to actually fly an airplane if they can't do this much...

Don't do them if you don't feel they'll be useful to you but don't condemn people who can do this stuff safely and see/find value in it. It's ludicrous to think you're going to automatically have an accident if you do HS taxi tests.

I did about 20 finding and solving my issues and I'm still here...
 
It seems many 'high speed taxi test' incidents occur when conducted by someone who is not ready to fly the plane. By ready, I mean preflight, buckled in, proficient and expecting a first flight. Taxi tests are pre-flight tests, not something to be conducted casually. The RV pilot that unexpectedly finds himself 50' above the runway is flying a plane that is not correctly configured for landing, and flying much differently than the RV he did his transition training in.

I've always discouraged RV builders from doing taxi tests any faster than...taxiing. But I have 'crow-hopped' much slower aircraft on a long runway as a precursor to first flight above the pattern. These simple, no-flap planes are closer to landing configuration than an RV that is on it first, unplanned flight.
 
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Don't do them if you don't feel they'll be useful to you but don't condemn people who can do this stuff safely and see/find value in it. It's ludicrous to think you're going to automatically have an accident if you do HS taxi tests.

We're not saying that all high speed taxi tests are dangerous. We just wanted to make it clear that it is not covered for Ground and Taxi Coverage, not to mention, it can be dangerous if you are unprepared for flight.
 
I can't believe I'm reading this!

I would probably be dead if I hadn't done high-speed taxi tests since on one run, a Nicopress sleeve on my rudder cable let go. Thankfully, although I was careening down the runway with no rudder control, I still had differential brakes because I had installed hard stops behind the normal travel of the pedals. Had this happened on the first flight, who knows what the outcome would would have been? (Yes, I flew my plane myself the first time.)

I also found that one of my brake master cylinders was defective and it kept locking up pressure in the right brake, much to the chagrin of the tire on that side. I must have looked like a drunken pilot weaving down the runway trying to keep the aircraft going straight. Using my Garmin Virb Elite, I also learned that my ASI was "pretty close", and I learned how many feet it took me to accelerate to near takeoff speed. That was a real concern in my case since the runway was only 2.900' long. In addition, I learned at what speed the rudder became effective. I learned how wimpy the brakes on my plane are, almost ground looping it at the end one time.

I definitely cast my vote for high-speed taxi testing.
 
I would probably be dead if I hadn't done high-speed taxi tests since on one run, a Nicopress sleeve on my rudder cable let go. Thankfully, although I was careening down the runway with no rudder control, I still had differential brakes because I had installed hard stops behind the normal travel of the pedals. Had this happened on the first flight, who knows what the outcome would would have been? (Yes, I flew my plane myself the first time.)

I also found that one of my brake master cylinders was defective and it kept locking up pressure in the right brake, much to the chagrin of the tire on that side. I must have looked like a drunken pilot weaving down the runway trying to keep the aircraft going straight. Using my Garmin Virb Elite, I also learned that my ASI was "pretty close", and I learned how many feet it took me to accelerate to near takeoff speed. That was a real concern in my case since the runway was only 2.900' long. In addition, I learned at what speed the rudder became effective. I learned how wimpy the brakes on my plane are, almost ground looping it at the end one time.

I definitely cast my vote for high-speed taxi testing.

Rudder Cables and Brake Systems can be tested on the ground, and should be tested BEFORE first engine start regardless of any taxi testing.
You got lucky, or are very skilled, as your first taxi could have been someone else's first accident.
 
The topic has come up before and there seems to outright fear in doing HS taxi tests.

Like I said before, no good plan in place by people getting airborne which is just scary.

I can't believe many people don't have their full insurance coverage in force before they head down a runway for any reason but then again we see professional pilots and even test pilots getting killed by failing to do control checks so maybe I shouldn't be surprised. That was my point about judgement.

Does anyone use checklists and test cards anymore?
 
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I can't believe many people don't have their full insurance coverage in force before they head down a runway for any reason but then again we see see professional pilots and even test pilots getting killed by failing to do control checks so maybe I shouldn't be surprised. That was my point about judgement.


When I lived on the "Left" coast, there was an airplane builder (not RV) that was doing taxi tests (slow speed not on runway) at the airport I was based at. His brakes failed and he hit a parked Glider trailer and damaged the glider inside plus did lots of damage to his airplane. If there had been insurance to cover the damage, it would have saved him a lot of money in damage costs to others property.

IMHO, one must have insurance before running the engine if not to replace damage to your own stuff but to fix damage to some else stuff.
 
I would probably be dead if I hadn't done high-speed taxi tests since on one run, a Nicopress sleeve on my rudder cable let go.

As an aside, properly installed Nicopress fittings, checked with the proper gauge, do not just let go. Ever. The cable fails before the fitting will slip.
 
YEP!

As an aside, properly installed Nicopress fittings, checked with the proper gauge, do not just let go. Ever. The cable fails before the fitting will slip.

99 times out of a hundred when a Nicopress fitting fails, it is because the wrong size was used. PLEASE be careful when selecting the fittings.
 
It seems many 'high speed taxi test' incidents occur when conducted by someone who is not ready to fly the plane. By ready, I mean preflight, buckled in, proficient and expecting a first flight. Taxi tests are pre-flight tests, not something to be conducted casually. The RV pilot that unexpectedly finds himself 50' above the runway is flying a plane that is not correctly configured for landing, and flying much differently than the RV he did his transition training in.

I've always discouraged RV builders from doing taxi tests any faster than...taxiing. But I have 'crow-hopped' much slower aircraft on a long runway as a precursor to first flight above the pattern. These simple, no-flap planes are closer to landing configuration than an RV that is on it first, unplanned flight.

Wait. I thought you...

Never mind. ;-)
 
...properly installed Nicopress fittings, checked with the proper gauge, do not just let go.
It wasn't properly installed. I originally used a cheap tool from ACS or A-T-S (can't remember) where you just tighten down a couple of bolts to smash the sleeve. The crimp failed. After replacing the cables, I used the proper tool that looks like a pair of bolt-cutters, and a go/nogo gauge. BTW, the second time I used the tin-plated copper sleeves that are recommended for stainless cables.
 
It wasn't properly installed. I originally used a cheap tool from ACS or A-T-S (can't remember) where you just tighten down a couple of bolts to smash the sleeve. The crimp failed. After replacing the cables, I used the proper tool that looks like a pair of bolt-cutters, and a go/nogo gauge. BTW, the second time I used the tin-plated copper sleeves that are recommended for stainless cables.

A tiny bit of thread creep....I've used the 'cheap two-bolt' nicopress tool for numerous cables and as long as the proper sleeve is used and the fitting passes the go/no go gauge test the integrity of the connection is just as good as one made with the large crimp tool....provided proper technique is used. The main difference between the two tools is the speed and ease of using the large leveraged tool. An advantage of the 'bolt' tool is how it can be used in confined spaces.

Back to our regular programming.....
 
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I am for taxi testing. I seem to be one of the few. When I taught flying lessons I always made sure the student was competent in handling the plane at taxi speeds that would be involved before and after the flight. This still makes sense to me. I cannot imagine the possibilities of what might happen to even an experienced pilot if they are not practiced and competent at handling the plane at fast taxi speed. To me this is a part of the flight just like turns and climbs. What is going to happen if you have to use a crosswind runway for your first landing because another plane had a flat tire or something and is blocking the big runway. What is going to happen is that you are going to be nervous and jerky while trying to land a strange plane that you have no experience in on a short runway with a crosswind. Good luck! I hope your insurance is current. I will get off my soap box now.
 
I am for taxi testing. I seem to be one of the few. When I taught flying lessons I always made sure the student was competent in handling the plane at taxi speeds that would be involved before and after the flight. This still makes sense to me. I cannot imagine the possibilities of what might happen to even an experienced pilot if they are not practiced and competent at handling the plane at fast taxi speed. To me this is a part of the flight just like turns and climbs. What is going to happen if you have to use a crosswind runway for your first landing because another plane had a flat tire or something and is blocking the big runway. What is going to happen is that you are going to be nervous and jerky while trying to land a strange plane that you have no experience in on a short runway with a crosswind. Good luck! I hope your insurance is current. I will get off my soap box now.

Isn't this the purpose of *transition training*?

Are you taxi testing the plane, or the pilot, here?
 
The easy answer is personal preference. I will not do high speed taxi runs myself as they lengthen the time of exposure at one of the trickier phases of flight, as opposed to transitioning through it fairly quickly. Much like step taxiing a float plane. Thats my reason....

But I'm sure there is good reasons for high speed taxi tests. Personally the risk outweighs the benefits for me but for others it may not. The decision is with the pilot.

Alex
 
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